In semiconductor manufacturing processes for devices beyond the 30 nm node, high dielectric constant (so-called “high-k”) materials are needed to meet performance requirements for high capacitance, low leakage, and low power consumption. High-k films are typically used to form capacitor dielectrics in Dynamic Random Access Memory (DRAM) devices, gate insulator layers in Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) or tunnel gate dielectrics in flash memory circuits, among other applications.
Hafnium oxide (HfO2) and zirconium oxide (ZrO2) are widely used high-k materials and offer higher dielectric constants than those of SiO2 and Al2O3, wide band gaps, high refractive indices, and good thermal stability. To further increase the dielectric constant of oxide materials, implantation of doping materials into HfO2 and ZrO2 have been explored, but the challenge remains of how to increase the k value, while maintaining low leakage current and high breakdown voltage.
A method of forming an apparatus having a dielectric containing cerium oxide and aluminum oxide is described in U.S. Pat. No. 7,754,618. Methods of forming crystallographically stabilized doped hafnium zirconium-based films are described in U.S. Pat. No. 7,833,913. U.S. Pre-grant publication 2012/0127629 describes a doped ZrO2 capacitor.